(a) Field of the Invention
This invention relates to pharmaceutical intermediates and their preparation process, and more specifically to novel 2-methylchromone derivatives represented by the general formula: ##STR2## wherein R.sub.1 means a hydrogen atom or a lower alkanoyl group and their preparation process.
As exemplary lower alkanoyl groups represented by R.sub.1, may be mentioned acetyl, propionyl, butyryl and isobutyryl groups and the like.
(b) Description of the Prior Art
As have been disclosed in Japanese Patent Laid-open Nos. 136292/80, 5487/81, 73087/81, 122384/81 and 45185/82, 7-phenylacetamido-3-cephem derivatives having the chromone nucleus have been known in recent years. These compounds have strong antibacterial activities against gram-negative bacteria, notably, Pseud. aeruginosa, Kleb. pneumoniae, Ser. marcescens and the like and are effective against a variety of infectious diseases. However, each of these compounds is primarily excreted into bile and only a little portion thereof is excreted into urine when administered. These compounds are still effective against infections of the urinary tract owing to their very strong antibacterial activities although only minor portions thereof are excreted into urine as mentioned above. However, there is a standing demand for the development of 7-phenylacetamido-3-cephem derivatives having higher excretion rates into urine.